import { describe, it, expect, beforeEach, afterEach } from "bun:test"
import { mkdirSync, writeFileSync, rmSync } from "fs"
import { join } from "path"
import { tmpdir } from "os"

const TEST_DIR = join(tmpdir(), "skill-loader-test-" + Date.now())
const SKILLS_DIR = join(TEST_DIR, ".opencode", "skills")

function createTestSkill(name: string, content: string, mcpJson?: object): string {
  const skillDir = join(SKILLS_DIR, name)
  mkdirSync(skillDir, { recursive: true })
  const skillPath = join(skillDir, "SKILL.md")
  writeFileSync(skillPath, content)
  if (mcpJson) {
    writeFileSync(join(skillDir, "mcp.json"), JSON.stringify(mcpJson, null, 2))
  }
  return skillDir
}

describe("skill loader MCP parsing", () => {
  beforeEach(() => {
    mkdirSync(TEST_DIR, { recursive: true })
  })

  afterEach(() => {
    rmSync(TEST_DIR, { recursive: true, force: true })
  })

  describe("parseSkillMcpConfig", () => {
    it("parses skill with nested MCP config", async () => {
      // given
      const skillContent = `---
name: test-skill
description: A test skill with MCP
mcp:
  sqlite:
    command: uvx
    args:
      - mcp-server-sqlite
      - --db-path
      - ./data.db
  memory:
    command: npx
    args: [-y, "@anthropic-ai/mcp-server-memory"]
---
This is the skill body.
`
      createTestSkill("test-mcp-skill", skillContent)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "test-skill")

        // then
        expect(skill).toBeDefined()
        expect(skill?.mcpConfig).toBeDefined()
        expect(skill?.mcpConfig?.sqlite).toBeDefined()
        expect(skill?.mcpConfig?.sqlite?.command).toBe("uvx")
        expect(skill?.mcpConfig?.sqlite?.args).toEqual([
          "mcp-server-sqlite",
          "--db-path",
          "./data.db"
        ])
        expect(skill?.mcpConfig?.memory).toBeDefined()
        expect(skill?.mcpConfig?.memory?.command).toBe("npx")
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("returns undefined mcpConfig for skill without MCP", async () => {
      // given
      const skillContent = `---
name: simple-skill
description: A simple skill without MCP
---
This is a simple skill.
`
      createTestSkill("simple-skill", skillContent)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "simple-skill")

        // then
        expect(skill).toBeDefined()
        expect(skill?.mcpConfig).toBeUndefined()
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("preserves env var placeholders without expansion", async () => {
      // given
      const skillContent = `---
name: env-skill
mcp:
  api-server:
    command: node
    args: [server.js]
    env:
      API_KEY: "\${API_KEY}"
      DB_PATH: "\${HOME}/data.db"
---
Skill with env vars.
`
      createTestSkill("env-skill", skillContent)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "env-skill")

        // then
        expect(skill?.mcpConfig?.["api-server"]?.env?.API_KEY).toBe("${API_KEY}")
        expect(skill?.mcpConfig?.["api-server"]?.env?.DB_PATH).toBe("${HOME}/data.db")
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("handles malformed YAML gracefully", async () => {
      // given - malformed YAML causes entire frontmatter to fail parsing
      const skillContent = `---
name: bad-yaml
mcp: [this is not valid yaml for mcp
---
Skill body.
`
      createTestSkill("bad-yaml-skill", skillContent)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        // then - when YAML fails, skill uses directory name as fallback
        const skill = skills.find(s => s.name === "bad-yaml-skill")

        expect(skill).toBeDefined()
        expect(skill?.mcpConfig).toBeUndefined()
      } finally {
        process.chdir(originalCwd)
      }
    })
  })

  describe("mcp.json file loading (AmpCode compat)", () => {
    it("loads MCP config from mcp.json with mcpServers format", async () => {
      // given
      const skillContent = `---
name: ampcode-skill
description: Skill with mcp.json
---
Skill body.
`
      const mcpJson = {
        mcpServers: {
          playwright: {
            command: "npx",
            args: ["@playwright/mcp@latest"]
          }
        }
      }
      createTestSkill("ampcode-skill", skillContent, mcpJson)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "ampcode-skill")

        // then
        expect(skill).toBeDefined()
        expect(skill?.mcpConfig).toBeDefined()
        expect(skill?.mcpConfig?.playwright).toBeDefined()
        expect(skill?.mcpConfig?.playwright?.command).toBe("npx")
        expect(skill?.mcpConfig?.playwright?.args).toEqual(["@playwright/mcp@latest"])
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("mcp.json takes priority over YAML frontmatter", async () => {
      // given
      const skillContent = `---
name: priority-skill
mcp:
  from-yaml:
    command: yaml-cmd
    args: [yaml-arg]
---
Skill body.
`
      const mcpJson = {
        mcpServers: {
          "from-json": {
            command: "json-cmd",
            args: ["json-arg"]
          }
        }
      }
      createTestSkill("priority-skill", skillContent, mcpJson)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "priority-skill")

        // then - mcp.json should take priority
        expect(skill?.mcpConfig?.["from-json"]).toBeDefined()
        expect(skill?.mcpConfig?.["from-yaml"]).toBeUndefined()
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("supports direct format without mcpServers wrapper", async () => {
      // given
      const skillContent = `---
name: direct-format
---
Skill body.
`
      const mcpJson = {
        sqlite: {
          command: "uvx",
          args: ["mcp-server-sqlite"]
        }
      }
      createTestSkill("direct-format", skillContent, mcpJson)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "direct-format")

        // then
        expect(skill?.mcpConfig?.sqlite).toBeDefined()
        expect(skill?.mcpConfig?.sqlite?.command).toBe("uvx")
      } finally {
        process.chdir(originalCwd)
      }
      })
  })

  describe("allowed-tools parsing", () => {
    it("parses space-separated allowed-tools string", async () => {
      // given
      const skillContent = `---
name: space-separated-tools
description: Skill with space-separated allowed-tools
allowed-tools: Read Write Edit Bash
---
Skill body.
`
      createTestSkill("space-separated-tools", skillContent)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "space-separated-tools")

        // then
        expect(skill).toBeDefined()
        expect(skill?.allowedTools).toEqual(["Read", "Write", "Edit", "Bash"])
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("parses YAML inline array allowed-tools", async () => {
      // given
      const skillContent = `---
name: yaml-inline-array
description: Skill with YAML inline array allowed-tools
allowed-tools: [Read, Write, Edit, Bash]
---
Skill body.
`
      createTestSkill("yaml-inline-array", skillContent)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "yaml-inline-array")

        // then
        expect(skill).toBeDefined()
        expect(skill?.allowedTools).toEqual(["Read", "Write", "Edit", "Bash"])
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("parses YAML multi-line array allowed-tools", async () => {
      // given
      const skillContent = `---
name: yaml-multiline-array
description: Skill with YAML multi-line array allowed-tools
allowed-tools:
  - Read
  - Write
  - Edit
  - Bash
---
Skill body.
`
      createTestSkill("yaml-multiline-array", skillContent)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "yaml-multiline-array")

        // then
        expect(skill).toBeDefined()
        expect(skill?.allowedTools).toEqual(["Read", "Write", "Edit", "Bash"])
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("returns undefined for skill without allowed-tools", async () => {
      // given
      const skillContent = `---
name: no-allowed-tools
description: Skill without allowed-tools field
---
Skill body.
`
      createTestSkill("no-allowed-tools", skillContent)

      // when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "no-allowed-tools")

        // then
        expect(skill).toBeDefined()
        expect(skill?.allowedTools).toBeUndefined()
      } finally {
        process.chdir(originalCwd)
      }
    })
  })

  describe("nested skill discovery", () => {
    it("discovers skills in nested directories (superpowers pattern)", async () => {
      // #given - simulate superpowers structure: skills/superpowers/brainstorming/SKILL.md
      const nestedDir = join(SKILLS_DIR, "superpowers", "brainstorming")
      mkdirSync(nestedDir, { recursive: true })
      const skillContent = `---
name: brainstorming
description: A nested skill for brainstorming
---
This is a nested skill.
`
      writeFileSync(join(nestedDir, "SKILL.md"), skillContent)

      // #when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name === "superpowers/brainstorming")

        // #then
        expect(skill).toBeDefined()
        expect(skill?.name).toBe("superpowers/brainstorming")
        expect(skill?.definition.description).toContain("brainstorming")
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("discovers multiple skills in nested directories", async () => {
      // #given - multiple nested skills
      const skills = ["brainstorming", "debugging", "testing"]
      for (const skillName of skills) {
        const nestedDir = join(SKILLS_DIR, "superpowers", skillName)
        mkdirSync(nestedDir, { recursive: true })
        writeFileSync(join(nestedDir, "SKILL.md"), `---
name: ${skillName}
description: ${skillName} skill
---
Content for ${skillName}.
`)
      }

      // #when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const discoveredSkills = await discoverSkills({ includeClaudeCodePaths: false })

        // #then
        for (const skillName of skills) {
          const skill = discoveredSkills.find(s => s.name === `superpowers/${skillName}`)
          expect(skill).toBeDefined()
        }
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("respects max depth limit", async () => {
      // #given - deeply nested skill (3 levels deep, beyond default maxDepth of 2)
      const deepDir = join(SKILLS_DIR, "level1", "level2", "level3", "deep-skill")
      mkdirSync(deepDir, { recursive: true })
      writeFileSync(join(deepDir, "SKILL.md"), `---
name: deep-skill
description: A deeply nested skill
---
Too deep.
`)

      // #when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })
        const skill = skills.find(s => s.name.includes("deep-skill"))

        // #then - should not find skill beyond maxDepth
        expect(skill).toBeUndefined()
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("flat skills still work alongside nested skills", async () => {
      // #given - both flat and nested skills
      const flatSkillDir = join(SKILLS_DIR, "flat-skill")
      mkdirSync(flatSkillDir, { recursive: true })
      writeFileSync(join(flatSkillDir, "SKILL.md"), `---
name: flat-skill
description: A flat skill
---
Flat content.
`)

      const nestedDir = join(SKILLS_DIR, "nested", "nested-skill")
      mkdirSync(nestedDir, { recursive: true })
      writeFileSync(join(nestedDir, "SKILL.md"), `---
name: nested-skill
description: A nested skill
---
Nested content.
`)

      // #when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })

        // #then - both should be found
        const flatSkill = skills.find(s => s.name === "flat-skill")
        const nestedSkill = skills.find(s => s.name === "nested/nested-skill")

        expect(flatSkill).toBeDefined()
        expect(nestedSkill).toBeDefined()
      } finally {
        process.chdir(originalCwd)
      }
    })

    it("prefers directory skill (SKILL.md) over file skill (*.md) on name collision", async () => {
      // #given - both foo.md file AND foo/SKILL.md directory exist
      // Directory skill should win (deterministic precedence: SKILL.md > {dir}.md > *.md)
      const dirSkillDir = join(SKILLS_DIR, "collision-test")
      mkdirSync(dirSkillDir, { recursive: true })
      writeFileSync(join(dirSkillDir, "SKILL.md"), `---
name: collision-test
description: Directory-based skill (should win)
---
I am the directory skill.
`)

      // Also create a file with same base name at parent level
      writeFileSync(join(SKILLS_DIR, "collision-test.md"), `---
name: collision-test
description: File-based skill (should lose)
---
I am the file skill.
`)

      // #when
      const { discoverSkills } = await import("./loader")
      const originalCwd = process.cwd()
      process.chdir(TEST_DIR)

      try {
        const skills = await discoverSkills({ includeClaudeCodePaths: false })

        // #then - only one skill should exist, and it should be the directory-based one
        const matchingSkills = skills.filter(s => s.name === "collision-test")
        expect(matchingSkills).toHaveLength(1)
        expect(matchingSkills[0]?.definition.description).toContain("Directory-based skill")
      } finally {
        process.chdir(originalCwd)
      }
    })
  })
})