// internal/skills/spec/handlers.go
package spec

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

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

type specArgs struct {
	ProjectRoot  string `json:"project_root"`
	Requirements string `json:"requirements"`
	OutputPath   string `json:"output_path"`
	Context      string `json:"context"`
	Model        string `json:"model"`
	SessionID    string `json:"session_id"`
}

// Handle dispatches the MCP tool call to the appropriate handler.
func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (json.RawMessage, error) {
	if tool != "spec" {
		return nil, fmt.Errorf("unknown tool: %s", tool)
	}
	var a specArgs
	if err := json.Unmarshal(args, &a); err != nil {
		return nil, fmt.Errorf("parse args: %w", err)
	}
	if a.ProjectRoot == "" {
		return nil, fmt.Errorf("project_root is required")
	}
	if a.Requirements == "" {
		return nil, fmt.Errorf("requirements is required")
	}
	outputPath := a.OutputPath
	if outputPath == "" {
		outputPath = "docs/spec.md"
	}

	model := a.Model
	if model == "" {
		model = s.cfg.DefaultModel
	}

	task := fmt.Sprintf(
		"phase: spec\nproject_root: %s\nrequirements: %s\noutput_path: %s\ncontext: %s\nmodel: %s",
		a.ProjectRoot, a.Requirements, outputPath, a.Context, model,
	)
	task = s.prependHistory(a.SessionID, "spec", task)

	if s.cfg.ExecutorFn == nil {
		return nil, fmt.Errorf("no executor configured")
	}
	result, err := s.cfg.ExecutorFn(ctx, iexec.Request{
		SkillPrompt: s.cfg.SkillPrompt,
		TaskPrompt:  task,
		Model:       model,
		Tools:       "Read,Write",
	})
	if err != nil {
		return nil, err
	}
	b, err := json.Marshal(result)
	if err != nil {
		return nil, fmt.Errorf("marshal result: %w", err)
	}
	return b, nil
}

func (s *Skill) prependHistory(sessionID, currentPhase, task string) string {
	if sessionID == "" || s.cfg.SessionsDir == "" {
		return task
	}
	entries, err := session.Read(s.cfg.SessionsDir, sessionID)
	if err != nil || len(entries) == 0 {
		return task
	}
	history := session.FormatHistory(entries, currentPhase)
	if history == "" {
		return task
	}
	return history + "\n---\n\n" + task
}