package gitea

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"
	
	"github.com/chorus-services/whoosh/internal/config"
)

// Client represents a Gitea API client
type Client struct {
	baseURL string
	token   string
	client  *http.Client
}

// Issue represents a Gitea issue
type Issue struct {
	ID          int64           `json:"id"`
	Number      int64           `json:"number"`
	Title       string          `json:"title"`
	Body        string          `json:"body"`
	State       string          `json:"state"`
	Labels      []Label         `json:"labels"`
	Assignees   []User          `json:"assignees"`
	CreatedAt   time.Time       `json:"created_at"`
	UpdatedAt   time.Time       `json:"updated_at"`
	ClosedAt    *time.Time      `json:"closed_at"`
	HTMLURL     string          `json:"html_url"`
	User        User            `json:"user"`
	Repository  IssueRepository `json:"repository,omitempty"`
}

// Label represents a Gitea issue label
type Label struct {
	ID          int64  `json:"id"`
	Name        string `json:"name"`
	Color       string `json:"color"`
	Description string `json:"description"`
}

// User represents a Gitea user
type User struct {
	ID       int64  `json:"id"`
	Login    string `json:"login"`
	FullName string `json:"full_name"`
	Email    string `json:"email"`
	AvatarURL string `json:"avatar_url"`
}

// Repository represents a Gitea repository
type Repository struct {
	ID          int64  `json:"id"`
	Name        string `json:"name"`
	FullName    string `json:"full_name"`
	Owner       User   `json:"owner"`
	Description string `json:"description"`
	Private     bool   `json:"private"`
	HTMLURL     string `json:"html_url"`
	CloneURL    string `json:"clone_url"`
	SSHURL      string `json:"ssh_url"`
	Language    string `json:"language"`
}

// IssueRepository represents the simplified repository info in issue responses
type IssueRepository struct {
	ID       int64  `json:"id"`
	Name     string `json:"name"`
	FullName string `json:"full_name"`
	Owner    string `json:"owner"` // Note: This is a string, not a User object
}

// NewClient creates a new Gitea API client
func NewClient(cfg config.GITEAConfig) *Client {
	token := cfg.Token
	// TODO: Handle TokenFile if needed
	
	return &Client{
		baseURL: cfg.BaseURL,
		token:   token,
		client: &http.Client{
			Timeout: 30 * time.Second,
		},
	}
}

// makeRequest makes an authenticated request to the Gitea API
func (c *Client) makeRequest(ctx context.Context, method, endpoint string) (*http.Response, error) {
	url := fmt.Sprintf("%s/api/v1%s", c.baseURL, endpoint)
	
	req, err := http.NewRequestWithContext(ctx, method, url, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}
	
	if c.token != "" {
		req.Header.Set("Authorization", "token "+c.token)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	
	resp, err := c.client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to make request: %w", err)
	}
	
	if resp.StatusCode >= 400 {
		defer resp.Body.Close()
		return nil, fmt.Errorf("API request failed with status %d", resp.StatusCode)
	}
	
	return resp, nil
}

// GetRepository retrieves repository information
func (c *Client) GetRepository(ctx context.Context, owner, repo string) (*Repository, error) {
	endpoint := fmt.Sprintf("/repos/%s/%s", url.PathEscape(owner), url.PathEscape(repo))
	
	resp, err := c.makeRequest(ctx, "GET", endpoint)
	if err != nil {
		return nil, fmt.Errorf("failed to get repository: %w", err)
	}
	defer resp.Body.Close()
	
	var repository Repository
	if err := json.NewDecoder(resp.Body).Decode(&repository); err != nil {
		return nil, fmt.Errorf("failed to decode repository: %w", err)
	}
	
	return &repository, nil
}

// GetIssues retrieves issues from a repository
func (c *Client) GetIssues(ctx context.Context, owner, repo string, opts IssueListOptions) ([]Issue, error) {
	endpoint := fmt.Sprintf("/repos/%s/%s/issues", url.PathEscape(owner), url.PathEscape(repo))
	
	// Add query parameters
	params := url.Values{}
	if opts.State != "" {
		params.Set("state", opts.State)
	}
	if opts.Labels != "" {
		params.Set("labels", opts.Labels)
	}
	if opts.Page > 0 {
		params.Set("page", strconv.Itoa(opts.Page))
	}
	if opts.Limit > 0 {
		params.Set("limit", strconv.Itoa(opts.Limit))
	}
	if !opts.Since.IsZero() {
		params.Set("since", opts.Since.Format(time.RFC3339))
	}
	
	if len(params) > 0 {
		endpoint += "?" + params.Encode()
	}
	
	resp, err := c.makeRequest(ctx, "GET", endpoint)
	if err != nil {
		return nil, fmt.Errorf("failed to get issues: %w", err)
	}
	defer resp.Body.Close()
	
	var issues []Issue
	if err := json.NewDecoder(resp.Body).Decode(&issues); err != nil {
		return nil, fmt.Errorf("failed to decode issues: %w", err)
	}
	
	// Set repository information on each issue for context
	for i := range issues {
		issues[i].Repository = IssueRepository{
			Name:     repo,
			FullName: fmt.Sprintf("%s/%s", owner, repo),
			Owner:    owner, // Now a string instead of User object
		}
	}
	
	return issues, nil
}

// GetIssue retrieves a specific issue
func (c *Client) GetIssue(ctx context.Context, owner, repo string, issueNumber int64) (*Issue, error) {
	endpoint := fmt.Sprintf("/repos/%s/%s/issues/%d", url.PathEscape(owner), url.PathEscape(repo), issueNumber)
	
	resp, err := c.makeRequest(ctx, "GET", endpoint)
	if err != nil {
		return nil, fmt.Errorf("failed to get issue: %w", err)
	}
	defer resp.Body.Close()
	
	var issue Issue
	if err := json.NewDecoder(resp.Body).Decode(&issue); err != nil {
		return nil, fmt.Errorf("failed to decode issue: %w", err)
	}
	
	// Set repository information
	issue.Repository = IssueRepository{
		Name:     repo,
		FullName: fmt.Sprintf("%s/%s", owner, repo),
		Owner:    owner, // Now a string instead of User object
	}
	
	return &issue, nil
}

// IssueListOptions contains options for listing issues
type IssueListOptions struct {
	State  string    // "open", "closed", "all"
	Labels string    // Comma-separated list of label names
	Page   int       // Page number (1-based)
	Limit  int       // Number of items per page (default: 20, max: 100)
	Since  time.Time // Only show issues updated after this time
}

// TestConnection tests the connection to Gitea API
func (c *Client) TestConnection(ctx context.Context) error {
	resp, err := c.makeRequest(ctx, "GET", "/user")
	if err != nil {
		return fmt.Errorf("connection test failed: %w", err)
	}
	defer resp.Body.Close()
	
	return nil
}

// WebhookPayload represents a Gitea webhook payload
type WebhookPayload struct {
	Action     string     `json:"action"`
	Number     int64      `json:"number,omitempty"`
	Issue      *Issue     `json:"issue,omitempty"`
	Repository Repository `json:"repository"`
	Sender     User       `json:"sender"`
}

// CreateLabelRequest represents the request to create a new label
type CreateLabelRequest struct {
	Name        string `json:"name"`
	Color       string `json:"color"`
	Description string `json:"description"`
}

// CreateLabel creates a new label in a repository
func (c *Client) CreateLabel(ctx context.Context, owner, repo string, label CreateLabelRequest) (*Label, error) {
	endpoint := fmt.Sprintf("/repos/%s/%s/labels", url.PathEscape(owner), url.PathEscape(repo))
	
	jsonData, err := json.Marshal(label)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal label data: %w", err)
	}
	
	req, err := http.NewRequestWithContext(ctx, "POST", fmt.Sprintf("%s/api/v1%s", c.baseURL, endpoint), strings.NewReader(string(jsonData)))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}
	
	if c.token != "" {
		req.Header.Set("Authorization", "token "+c.token)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	
	resp, err := c.client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to make request: %w", err)
	}
	defer resp.Body.Close()
	
	if resp.StatusCode >= 400 {
		return nil, fmt.Errorf("API request failed with status %d", resp.StatusCode)
	}
	
	var createdLabel Label
	if err := json.NewDecoder(resp.Body).Decode(&createdLabel); err != nil {
		return nil, fmt.Errorf("failed to decode label: %w", err)
	}
	
	return &createdLabel, nil
}

// GetLabels retrieves all labels from a repository
func (c *Client) GetLabels(ctx context.Context, owner, repo string) ([]Label, error) {
	endpoint := fmt.Sprintf("/repos/%s/%s/labels", url.PathEscape(owner), url.PathEscape(repo))
	
	resp, err := c.makeRequest(ctx, "GET", endpoint)
	if err != nil {
		return nil, fmt.Errorf("failed to get labels: %w", err)
	}
	defer resp.Body.Close()
	
	var labels []Label
	if err := json.NewDecoder(resp.Body).Decode(&labels); err != nil {
		return nil, fmt.Errorf("failed to decode labels: %w", err)
	}
	
	return labels, nil
}

// EnsureRequiredLabels ensures that required labels exist in the repository
func (c *Client) EnsureRequiredLabels(ctx context.Context, owner, repo string) error {
	requiredLabels := []CreateLabelRequest{
		{
			Name:        "bzzz-task",
			Color:       "ff6b6b",
			Description: "Issues that should be converted to BZZZ tasks for CHORUS",
		},
		{
			Name:        "whoosh-monitored",
			Color:       "4ecdc4", 
			Description: "Repository is monitored by WHOOSH",
		},
		{
			Name:        "priority-high",
			Color:       "e74c3c",
			Description: "High priority task for immediate attention",
		},
		{
			Name:        "priority-medium",
			Color:       "f39c12",
			Description: "Medium priority task",
		},
		{
			Name:        "priority-low",
			Color:       "95a5a6",
			Description: "Low priority task",
		},
	}
	
	// Get existing labels
	existingLabels, err := c.GetLabels(ctx, owner, repo)
	if err != nil {
		return fmt.Errorf("failed to get existing labels: %w", err)
	}
	
	// Create a map of existing label names for quick lookup
	existingLabelNames := make(map[string]bool)
	for _, label := range existingLabels {
		existingLabelNames[label.Name] = true
	}
	
	// Create missing required labels
	for _, requiredLabel := range requiredLabels {
		if !existingLabelNames[requiredLabel.Name] {
			_, err := c.CreateLabel(ctx, owner, repo, requiredLabel)
			if err != nil {
				return fmt.Errorf("failed to create label %s: %w", requiredLabel.Name, err)
			}
		}
	}
	
	return nil
}