package commands

import (
	"bytes"
	"encoding/json"
	"fmt"

	"git.hangman-lab.top/zhi/HarborForge.Cli/internal/client"
	"git.hangman-lab.top/zhi/HarborForge.Cli/internal/config"
	"git.hangman-lab.top/zhi/HarborForge.Cli/internal/output"
)

// taskResponse matches the backend TaskResponse schema.
type taskResponse struct {
	ID            int     `json:"id"`
	Code          string  `json:"code"`
	Title         string  `json:"title"`
	Description   *string `json:"description"`
	Status        string  `json:"status"`
	Priority      string  `json:"priority"`
	Type          string  `json:"type"`
	DueDate       *string `json:"due_date"`
	ProjectCode   string  `json:"project_code"`
	MilestoneCode *string `json:"milestone_code"`
	TakenBy       *string `json:"taken_by"`
	CreatedAt     string  `json:"created_at"`
}

// RunTaskList implements `hf task list`.
func RunTaskList(args []string, tokenFlag string) {
	token := ResolveToken(tokenFlag)

	query := ""
	for i := 0; i < len(args); i++ {
		switch args[i] {
		case "--project":
			if i+1 >= len(args) {
				output.Error("--project requires a value")
			}
			i++
			query = appendQuery(query, "project", args[i])
		case "--milestone":
			if i+1 >= len(args) {
				output.Error("--milestone requires a value")
			}
			i++
			query = appendQuery(query, "milestone", args[i])
		case "--status":
			if i+1 >= len(args) {
				output.Error("--status requires a value")
			}
			i++
			query = appendQuery(query, "status", args[i])
		case "--taken-by":
			if i+1 >= len(args) {
				output.Error("--taken-by requires a value")
			}
			i++
			query = appendQuery(query, "taken_by", args[i])
		case "--due-today":
			if i+1 >= len(args) {
				output.Error("--due-today requires a value")
			}
			i++
			query = appendQuery(query, "due_today", args[i])
		case "--order-by":
			if i+1 >= len(args) {
				output.Error("--order-by requires a value")
			}
			i++
			query = appendQuery(query, "order_by", args[i])
		default:
			output.Errorf("unknown flag: %s", args[i])
		}
	}

	cfg, err := config.Load()
	if err != nil {
		output.Errorf("config error: %v", err)
	}
	c := client.New(cfg.BaseURL, token)
	path := "/tasks"
	if query != "" {
		path += "?" + query
	}
	data, err := c.Get(path)
	if err != nil {
		output.Errorf("failed to list tasks: %v", err)
	}

	if output.JSONMode {
		var raw json.RawMessage
		if err := json.Unmarshal(data, &raw); err != nil {
			output.Errorf("invalid JSON response: %v", err)
		}
		output.PrintJSON(raw)
		return
	}

	var tasks []taskResponse
	if err := json.Unmarshal(data, &tasks); err != nil {
		output.Errorf("cannot parse task list: %v", err)
	}

	headers := []string{"CODE", "TITLE", "STATUS", "PRIORITY", "TAKEN BY", "PROJECT"}
	var rows [][]string
	for _, t := range tasks {
		takenBy := ""
		if t.TakenBy != nil {
			takenBy = *t.TakenBy
		}
		title := t.Title
		if len(title) > 40 {
			title = title[:37] + "..."
		}
		rows = append(rows, []string{t.Code, title, t.Status, t.Priority, takenBy, t.ProjectCode})
	}
	output.PrintTable(headers, rows)
}

// RunTaskGet implements `hf task get <task-code>`.
func RunTaskGet(taskCode, tokenFlag string) {
	token := ResolveToken(tokenFlag)
	cfg, err := config.Load()
	if err != nil {
		output.Errorf("config error: %v", err)
	}
	c := client.New(cfg.BaseURL, token)
	data, err := c.Get("/tasks/" + taskCode)
	if err != nil {
		output.Errorf("failed to get task: %v", err)
	}

	if output.JSONMode {
		var raw json.RawMessage
		if err := json.Unmarshal(data, &raw); err != nil {
			output.Errorf("invalid JSON response: %v", err)
		}
		output.PrintJSON(raw)
		return
	}

	var t taskResponse
	if err := json.Unmarshal(data, &t); err != nil {
		output.Errorf("cannot parse task: %v", err)
	}

	desc := ""
	if t.Description != nil {
		desc = *t.Description
	}
	due := ""
	if t.DueDate != nil {
		due = *t.DueDate
	}
	milestone := ""
	if t.MilestoneCode != nil {
		milestone = *t.MilestoneCode
	}
	takenBy := ""
	if t.TakenBy != nil {
		takenBy = *t.TakenBy
	}
	output.PrintKeyValue(
		"code", t.Code,
		"title", t.Title,
		"description", desc,
		"status", t.Status,
		"priority", t.Priority,
		"type", t.Type,
		"due-date", due,
		"project", t.ProjectCode,
		"milestone", milestone,
		"taken-by", takenBy,
		"created", t.CreatedAt,
	)
}

// RunTaskCreate implements `hf task create`.
func RunTaskCreate(args []string, tokenFlag string) {
	token := ResolveToken(tokenFlag)

	project, title, milestone, taskType, priority, desc := "", "", "", "", "", ""
	for i := 0; i < len(args); i++ {
		switch args[i] {
		case "--project":
			if i+1 >= len(args) {
				output.Error("--project requires a value")
			}
			i++
			project = args[i]
		case "--title":
			if i+1 >= len(args) {
				output.Error("--title requires a value")
			}
			i++
			title = args[i]
		case "--milestone":
			if i+1 >= len(args) {
				output.Error("--milestone requires a value")
			}
			i++
			milestone = args[i]
		case "--type":
			if i+1 >= len(args) {
				output.Error("--type requires a value")
			}
			i++
			taskType = args[i]
		case "--priority":
			if i+1 >= len(args) {
				output.Error("--priority requires a value")
			}
			i++
			priority = args[i]
		case "--desc":
			if i+1 >= len(args) {
				output.Error("--desc requires a value")
			}
			i++
			desc = args[i]
		default:
			output.Errorf("unknown flag: %s", args[i])
		}
	}

	if project == "" || title == "" {
		output.Error("usage: hf task create --project <project-code> --title <title>")
	}

	// story/* types are restricted — must be created via `hf proposal accept`
	if taskType == "story" || (len(taskType) > 6 && taskType[:6] == "story/") {
		output.Error("story tasks are restricted and cannot be created directly.\nUse 'hf proposal accept <proposal-code> --milestone <milestone-code>' to generate story tasks from a proposal.")
	}

	payload := map[string]interface{}{
		"project_code": project,
		"title":        title,
	}
	if milestone != "" {
		payload["milestone_code"] = milestone
	}
	if taskType != "" {
		payload["type"] = taskType
	}
	if priority != "" {
		payload["priority"] = priority
	}
	if desc != "" {
		payload["description"] = desc
	}

	body, err := json.Marshal(payload)
	if err != nil {
		output.Errorf("cannot marshal payload: %v", err)
	}

	cfg, err := config.Load()
	if err != nil {
		output.Errorf("config error: %v", err)
	}
	c := client.New(cfg.BaseURL, token)
	data, err := c.Post("/tasks", bytes.NewReader(body))
	if err != nil {
		output.Errorf("failed to create task: %v", err)
	}

	if output.JSONMode {
		var raw json.RawMessage
		if err := json.Unmarshal(data, &raw); err != nil {
			output.Errorf("invalid JSON response: %v", err)
		}
		output.PrintJSON(raw)
		return
	}

	var t taskResponse
	if err := json.Unmarshal(data, &t); err != nil {
		fmt.Printf("task created: %s\n", title)
		return
	}
	fmt.Printf("task created: %s (code: %s)\n", t.Title, t.Code)
}

// RunTaskUpdate implements `hf task update <task-code>`.
func RunTaskUpdate(taskCode string, args []string, tokenFlag string) {
	token := ResolveToken(tokenFlag)

	payload := make(map[string]interface{})
	for i := 0; i < len(args); i++ {
		switch args[i] {
		case "--title":
			if i+1 >= len(args) {
				output.Error("--title requires a value")
			}
			i++
			payload["title"] = args[i]
		case "--desc":
			if i+1 >= len(args) {
				output.Error("--desc requires a value")
			}
			i++
			payload["description"] = args[i]
		case "--status":
			if i+1 >= len(args) {
				output.Error("--status requires a value")
			}
			i++
			payload["status"] = args[i]
		case "--priority":
			if i+1 >= len(args) {
				output.Error("--priority requires a value")
			}
			i++
			payload["priority"] = args[i]
		case "--assignee":
			if i+1 >= len(args) {
				output.Error("--assignee requires a value")
			}
			i++
			val := args[i]
			if val == "null" {
				payload["taken_by"] = nil
			} else {
				payload["taken_by"] = val
			}
		default:
			output.Errorf("unknown flag: %s", args[i])
		}
	}

	if len(payload) == 0 {
		output.Error("nothing to update — provide at least one flag")
	}

	body, err := json.Marshal(payload)
	if err != nil {
		output.Errorf("cannot marshal payload: %v", err)
	}

	cfg, err := config.Load()
	if err != nil {
		output.Errorf("config error: %v", err)
	}
	c := client.New(cfg.BaseURL, token)
	_, err = c.Patch("/tasks/"+taskCode, bytes.NewReader(body))
	if err != nil {
		output.Errorf("failed to update task: %v", err)
	}

	fmt.Printf("task updated: %s\n", taskCode)
}

// RunTaskTransition implements `hf task transition <task-code> <status>`.
func RunTaskTransition(taskCode, status, tokenFlag string) {
	token := ResolveToken(tokenFlag)

	payload := map[string]interface{}{
		"status": status,
	}
	body, err := json.Marshal(payload)
	if err != nil {
		output.Errorf("cannot marshal payload: %v", err)
	}

	cfg, err := config.Load()
	if err != nil {
		output.Errorf("config error: %v", err)
	}
	c := client.New(cfg.BaseURL, token)
	_, err = c.Post("/tasks/"+taskCode+"/transition", bytes.NewReader(body))
	if err != nil {
		output.Errorf("failed to transition task: %v", err)
	}

	fmt.Printf("task %s transitioned to %s\n", taskCode, status)
}

// RunTaskTake implements `hf task take <task-code>`.
func RunTaskTake(taskCode, tokenFlag string) {
	token := ResolveToken(tokenFlag)

	cfg, err := config.Load()
	if err != nil {
		output.Errorf("config error: %v", err)
	}
	c := client.New(cfg.BaseURL, token)
	_, err = c.Post("/tasks/"+taskCode+"/take", nil)
	if err != nil {
		output.Errorf("failed to take task: %v", err)
	}

	fmt.Printf("task taken: %s\n", taskCode)
}

// RunTaskDelete implements `hf task delete <task-code>`.
func RunTaskDelete(taskCode, tokenFlag string) {
	token := ResolveToken(tokenFlag)
	cfg, err := config.Load()
	if err != nil {
		output.Errorf("config error: %v", err)
	}
	c := client.New(cfg.BaseURL, token)
	_, err = c.Delete("/tasks/" + taskCode)
	if err != nil {
		output.Errorf("failed to delete task: %v", err)
	}
	fmt.Printf("task deleted: %s\n", taskCode)
}

// RunTaskSearch implements `hf task search`.
func RunTaskSearch(args []string, tokenFlag string) {
	token := ResolveToken(tokenFlag)

	query := ""
	for i := 0; i < len(args); i++ {
		switch args[i] {
		case "--query":
			if i+1 >= len(args) {
				output.Error("--query requires a value")
			}
			i++
			query = appendQuery(query, "q", args[i])
		case "--project":
			if i+1 >= len(args) {
				output.Error("--project requires a value")
			}
			i++
			query = appendQuery(query, "project", args[i])
		case "--status":
			if i+1 >= len(args) {
				output.Error("--status requires a value")
			}
			i++
			query = appendQuery(query, "status", args[i])
		default:
			output.Errorf("unknown flag: %s", args[i])
		}
	}

	cfg, err := config.Load()
	if err != nil {
		output.Errorf("config error: %v", err)
	}
	c := client.New(cfg.BaseURL, token)
	path := "/tasks/search"
	if query != "" {
		path += "?" + query
	}
	data, err := c.Get(path)
	if err != nil {
		output.Errorf("failed to search tasks: %v", err)
	}

	if output.JSONMode {
		var raw json.RawMessage
		if err := json.Unmarshal(data, &raw); err != nil {
			output.Errorf("invalid JSON response: %v", err)
		}
		output.PrintJSON(raw)
		return
	}

	var tasks []taskResponse
	if err := json.Unmarshal(data, &tasks); err != nil {
		output.Errorf("cannot parse task list: %v", err)
	}

	headers := []string{"CODE", "TITLE", "STATUS", "PRIORITY", "TAKEN BY", "PROJECT"}
	var rows [][]string
	for _, t := range tasks {
		takenBy := ""
		if t.TakenBy != nil {
			takenBy = *t.TakenBy
		}
		title := t.Title
		if len(title) > 40 {
			title = title[:37] + "..."
		}
		rows = append(rows, []string{t.Code, title, t.Status, t.Priority, takenBy, t.ProjectCode})
	}
	output.PrintTable(headers, rows)
}