package pullrequest

import (
	"context"
	"log/slog"
	"net/http"
	"strings"

	httpCtx "forge.cadoles.com/wpetit/clearcase/internal/http/context"
	"forge.cadoles.com/wpetit/clearcase/internal/http/form"
	"forge.cadoles.com/wpetit/clearcase/internal/http/handler/webui/common"
	"forge.cadoles.com/wpetit/clearcase/internal/http/handler/webui/pullrequest/component"

	"github.com/a-h/templ"
	"github.com/pkg/errors"
)

func (h *Handler) getPullRequestPage(w http.ResponseWriter, r *http.Request) {
	vmodel, err := h.fillPullRequestPageVModel(r)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	pr := component.PullRequestPage(*vmodel)
	templ.Handler(pr).ServeHTTP(w, r)
}

func (h *Handler) fillPullRequestPageVModel(r *http.Request) (*component.PullRequestPageVModel, error) {
	vmodel := &component.PullRequestPageVModel{
		SummaryForm:     component.NewPullRequestSummaryForm(),
		PullRequestForm: component.NewPullRequestForm(),
	}

	err := common.FillViewModel(
		r.Context(), vmodel, r,
		h.fillPullRequestPageSelectedProject,
		h.fillPullRequestPagePullRequests,
		h.fillPullRequestPageProjects,
		h.fillPullRequestPageSelectedPullRequest,
		h.fillPullRequestPageSummary,
	)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return vmodel, nil
}

func (h *Handler) fillPullRequestPageProjects(ctx context.Context, vmodel *component.PullRequestPageVModel, r *http.Request) error {
	user := httpCtx.User(ctx)

	projects, err := h.forge.GetUserProjects(ctx, user)
	if err != nil {
		return errors.WithStack(err)
	}

	vmodel.Projects = projects

	return nil
}

func (h *Handler) fillPullRequestPagePullRequests(ctx context.Context, vmodel *component.PullRequestPageVModel, r *http.Request) error {
	if vmodel.SelectedProjectID == "" {
		return nil
	}

	user := httpCtx.User(ctx)

	pullRequests, err := h.forge.GetUserProjectOpenedPullRequests(ctx, user, vmodel.SelectedProjectID)
	if err != nil {
		return errors.WithStack(err)
	}

	vmodel.PullRequests = pullRequests

	return nil
}

func (h *Handler) fillPullRequestPageSelectedProject(ctx context.Context, vmodel *component.PullRequestPageVModel, r *http.Request) error {
	project := r.URL.Query().Get("project")
	if project == "" {
		return nil
	}

	vmodel.SelectedProjectID = project
	vmodel.SummaryForm.Field("project").Set("value", project)

	return nil
}

func (h *Handler) fillPullRequestPageSelectedPullRequest(ctx context.Context, vmodel *component.PullRequestPageVModel, r *http.Request) error {
	pullRequest := r.URL.Query().Get("pullrequest")
	if pullRequest == "" {
		return nil
	}

	vmodel.SelectedPullRequestID = pullRequest
	vmodel.SummaryForm.Field("pullrequest").Set("value", pullRequest)

	return nil
}

func (h *Handler) fillPullRequestPageSummary(ctx context.Context, vmodel *component.PullRequestPageVModel, r *http.Request) error {
	if vmodel.SelectedProjectID == "" || vmodel.SelectedPullRequestID == "" {
		return nil
	}

	user := httpCtx.User(ctx)

	pullRequest, err := h.forge.GetUserProjectPullRequest(ctx, user, vmodel.SelectedProjectID, vmodel.SelectedPullRequestID)
	if err != nil {
		slog.ErrorContext(ctx, "could not retrieve selected pull request", slog.Any("error", errors.WithStack(err)))
		return nil
	}

	vmodel.SummaryForm.Field("summary").Set("value", pullRequest.Body)

	return nil
}

func (h *Handler) handlePullRequestSummaryForm(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	pullRequestSummaryForm := component.NewPullRequestSummaryForm()

	if err := pullRequestSummaryForm.Handle(r); err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	vmodel, err := h.fillPullRequestPageVModel(r)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	vmodel.SummaryForm = pullRequestSummaryForm

	if errs := pullRequestSummaryForm.Validate(); errs != nil {
		page := component.PullRequestPage(*vmodel)
		templ.Handler(page).ServeHTTP(w, r)

		return
	}

	projectID, err := form.FormFieldAttr[string](pullRequestSummaryForm, "project", "value")
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	pullRequestID, err := form.FormFieldAttr[string](pullRequestSummaryForm, "pullrequest", "value")
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	prSummary, err := form.FormFieldAttr[string](pullRequestSummaryForm, "summary", "value")
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	prTemplate, err := form.FormFieldAttr[string](pullRequestSummaryForm, "template", "value")
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	prTemplate = strings.TrimSpace(prTemplate)

	prTitle, prBody, prTips, err := h.forge.GeneratePullRequest(ctx, httpCtx.User(ctx), projectID, pullRequestID, prSummary, prTemplate)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	vmodel.PullRequestTips = prTips
	vmodel.PullRequestForm.Field("title").Set("value", prTitle)
	vmodel.PullRequestForm.Field("body").Set("value", prBody)

	page := component.PullRequestPage(*vmodel)
	templ.Handler(page).ServeHTTP(w, r)
}

func (h *Handler) handlePullRequestForm(w http.ResponseWriter, r *http.Request) {
	pullRequestForm := component.NewPullRequestForm()

	if err := pullRequestForm.Handle(r); err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	vmodel, err := h.fillPullRequestPageVModel(r)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	if errs := pullRequestForm.Validate(); errs != nil {
		vmodel.PullRequestForm = pullRequestForm

		page := component.PullRequestPage(*vmodel)
		templ.Handler(page).ServeHTTP(w, r)

		return
	}

	projectID := r.URL.Query().Get("project")
	pullRequestID := r.URL.Query().Get("pullrequest")

	title, err := form.FormFieldAttr[string](pullRequestForm, "title", "value")
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	body, err := form.FormFieldAttr[string](pullRequestForm, "body", "value")
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	ctx := r.Context()
	user := httpCtx.User(ctx)

	issueURL, err := h.forge.UpdatePullRequest(ctx, user, projectID, pullRequestID, title, body)
	if err != nil {
		h.handleError(w, r, errors.WithStack(err))
		return
	}

	vmodel.PullRequestURL = issueURL

	vmodel.SummaryForm.Field("summary").Set("value", "")
	vmodel.PullRequestForm.Field("title").Set("value", "")
	vmodel.PullRequestForm.Field("body").Set("value", "")

	page := component.PullRequestPage(*vmodel)
	templ.Handler(page).ServeHTTP(w, r)
}