package tdd

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	iexec "github.com/mathiasbq/supervisor/internal/exec"
	"github.com/mathiasbq/supervisor/internal/session"
)

func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (json.RawMessage, error) {
	switch tool {
	case "tdd_red":
		return s.handleRed(ctx, args)
	case "tdd_green":
		return s.handleGreen(ctx, args)
	case "tdd_refactor":
		return s.handleRefactor(ctx, args)
	default:
		return nil, fmt.Errorf("unknown tool: %s", tool)
	}
}

type redArgs struct {
	ProjectRoot string `json:"project_root"`
	Spec        string `json:"spec"`
	Model       string `json:"model"`
	TestCmd     string `json:"test_cmd"`
}

func (s *Skill) handleRed(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args redArgs
	if err := json.Unmarshal(raw, &args); err != nil {
		return nil, fmt.Errorf("parse args: %w", err)
	}
	if args.ProjectRoot == "" {
		return nil, fmt.Errorf("project_root is required")
	}
	if args.Spec == "" {
		return nil, fmt.Errorf("spec is required")
	}
	task := fmt.Sprintf(
		"phase: red\nproject_root: %s\nspec: %s\nmodel: %s\ntest_cmd: %s",
		args.ProjectRoot, args.Spec, s.resolveModel(args.Model), args.TestCmd,
	)
	return s.execute(ctx, task)
}

type greenArgs struct {
	ProjectRoot string `json:"project_root"`
	TestPath    string `json:"test_path"`
	Model       string `json:"model"`
	TestCmd     string `json:"test_cmd"`
	SessionID   string `json:"session_id"`
}

func (s *Skill) handleGreen(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args greenArgs
	if err := json.Unmarshal(raw, &args); err != nil {
		return nil, fmt.Errorf("parse args: %w", err)
	}
	if args.ProjectRoot == "" {
		return nil, fmt.Errorf("project_root is required")
	}
	if args.TestPath == "" {
		return nil, fmt.Errorf("test_path is required")
	}
	task := fmt.Sprintf(
		"phase: green\nproject_root: %s\ntest_path: %s\nmodel: %s\ntest_cmd: %s",
		args.ProjectRoot, args.TestPath, s.resolveModel(args.Model), args.TestCmd,
	)
	task = session.PrependHistory(s.cfg.SessionsDir, args.SessionID, "green", task)

	t0 := time.Now()
	result, err := s.execute(ctx, task)
	if err != nil {
		return nil, err
	}
	s.logAttempt(args.SessionID, args.ProjectRoot, "tdd", "green", t0, result)
	return result, nil
}

type refactorArgs struct {
	ProjectRoot string `json:"project_root"`
	TestPath    string `json:"test_path"`
	ImplPath    string `json:"impl_path"`
	Model       string `json:"model"`
	TestCmd     string `json:"test_cmd"`
	SessionID   string `json:"session_id"`
}

func (s *Skill) handleRefactor(ctx context.Context, raw json.RawMessage) (json.RawMessage, error) {
	var args refactorArgs
	if err := json.Unmarshal(raw, &args); err != nil {
		return nil, fmt.Errorf("parse args: %w", err)
	}
	if args.ProjectRoot == "" {
		return nil, fmt.Errorf("project_root is required")
	}
	if args.TestPath == "" {
		return nil, fmt.Errorf("test_path is required")
	}
	if args.ImplPath == "" {
		return nil, fmt.Errorf("impl_path is required")
	}
	task := fmt.Sprintf(
		"phase: refactor\nproject_root: %s\ntest_path: %s\nimpl_path: %s\nmodel: %s\ntest_cmd: %s",
		args.ProjectRoot, args.TestPath, args.ImplPath, s.resolveModel(args.Model), args.TestCmd,
	)
	task = session.PrependHistory(s.cfg.SessionsDir, args.SessionID, "refactor", task)

	t0 := time.Now()
	result, err := s.execute(ctx, task)
	if err != nil {
		return nil, err
	}
	s.logAttempt(args.SessionID, args.ProjectRoot, "tdd", "refactor", t0, result)
	return result, nil
}

func (s *Skill) resolveModel(override string) string {
	if override != "" {
		return override
	}
	return s.cfg.DefaultModel
}

// execute calls ExecutorFn and returns the marshaled result.
func (s *Skill) execute(ctx context.Context, task string) (json.RawMessage, error) {
	if s.cfg.ExecutorFn == nil {
		return nil, fmt.Errorf("no executor configured")
	}
	req := iexec.Request{
		SkillPrompt: s.cfg.SkillPrompt,
		TaskPrompt:  task,
	}
	result, err := s.cfg.ExecutorFn(ctx, req)
	if err != nil {
		return nil, err
	}
	return json.Marshal(result)
}

// logAttempt writes a session.Entry for a completed phase if session_id is set.
// raw is the marshaled Result returned by execute; we unmarshal to extract fields.
func (s *Skill) logAttempt(sessionID, projectRoot, skill, phase string, t0 time.Time, raw json.RawMessage) {
	if sessionID == "" || s.cfg.SessionsDir == "" {
		return
	}
	var result iexec.Result
	if err := json.Unmarshal(raw, &result); err != nil {
		return
	}
	_ = session.Append(s.cfg.SessionsDir, sessionID, session.Entry{
		SessionID:   sessionID,
		Timestamp:   time.Now(),
		Skill:       skill,
		Phase:       phase,
		ProjectRoot: projectRoot,
		Attempts:    session.AttemptsFrom(result.Attempts),
		FinalStatus: result.Status,
		FilePath:    result.FilePath,
		ModelUsed:   result.ModelUsed,
		DurationMs:  time.Since(t0).Milliseconds(),
		Message:     result.Message,
	})
}